ddi_get_devstate

Synopsis

Interface Level

Solaris DDI specific (Solaris DDI)

Parameters

dip

Pointer to the device's dev_info structure

Description

The ddi_get_devstate() function returns a value indicating the state of the device specified
by dip, as derived from the configuration operations that have been performed
on it (or on the bus on which it resides) and any
fault reports relating to it.

Return Values

DDI_DEVSTATE_OFFLINE

The device is offline. In this state, the device driver is not attached, nor will it be attached automatically. The device cannot be used until it is brought online.

DDI_DEVSTATE_DOWN

The device is online but unusable due to a fault.

DDI_DEVSTATE_QUIESCED

The bus on which the device resides has been quiesced. This is not a fault, but no operations on the device should be performed while the bus remains quiesced.

DDI_DEVSTATE_DEGRADED

The device is online but only able to provide a partial or degraded service, due to a fault.

DDI_DEVSTATE_UP

The device is online and fully operational.

Context

The ddi_get_devstate() function may be called from user, kernel, or interrupt context.

Notes

A device driver should call this function to check its own state
at each major entry point, and before committing resources to a requested
operation. If a driver discovers that its device is already down,
it should perform required cleanup actions and return as soon as possible.
If appropriate, it should return an error to its caller, indicating that
the device has failed (for example, a driver's read(9E) routine would return
EIO).

Depending on the driver, some non-I/O operations (for example, calls to the
driver's ioctl(9E) routine) may still succeed; only functions which would require fully accessible
and operational hardware will necessarily fail. If the bus on which the
device resides is quiesced, the driver may return a value indicating the
operation should be retried later (for example, EAGAIN). Alternatively, for some
classes of device, it may be appropriate for the driver to enqueue the
operation and service it once the bus has been unquiesced. Note
that not all busses support the quiesce/unquiesce operations, so this value may
never be seen by some drivers.